Bug 1937785 - Remove nsPresContext::mKeyboardHeight and introduce MobileViewportManager::mPendingKeyboardHeight. r=botond

There's a race condition where the keyboard height change notification
has arrived but nsDocumentViewer size change hasn't yet arrived.

MobileViewportManager::mPendingKeyboardHeight is introduced to fix the race.

Differential Revision: https://phabricator.services.mozilla.com/D234262

layout/base/MobileViewportManager.cpp

@@ -648,6 +648,12 @@ void MobileViewportManager::RefreshViewportSize(bool aForceAdjustResolution) {
     return;
   }
 
+  // Now it's time to update the keyboard height
+  if (mPendingKeyboardHeight) {
+    mKeyboardHeight = *mPendingKeyboardHeight;
+    mPendingKeyboardHeight.reset();
+  }
+
   nsViewportInfo viewportInfo =
       mContext->GetViewportInfo(GetLayoutDisplaySize());
   MVM_LOG("%p: viewport info has zooms min=%f max=%f default=%f,valid=%d\n",
@@ -760,10 +766,11 @@ ParentLayerSize MobileViewportManager::GetCompositionSizeWithoutDynamicToolbar()
 
 void MobileViewportManager::UpdateKeyboardHeight(
     ScreenIntCoord aKeyboardHeight) {
-  if (aKeyboardHeight == mKeyboardHeight) {
+  if (mPendingKeyboardHeight == Some(aKeyboardHeight)) {
     return;
   }
-  mKeyboardHeight = aKeyboardHeight;
+
+  mPendingKeyboardHeight = Some(aKeyboardHeight);
   mInvalidViewport = true;
 }
 

layout/base/MobileViewportManager.h

@@ -153,6 +153,8 @@ class MobileViewportManager final : public nsIDOMEventListener,
    */
   nsRect InitialVisibleArea();
 
+  mozilla::ScreenIntCoord GetKeyboardHeight() const { return mKeyboardHeight; }
+
  private:
   ~MobileViewportManager();
 
@@ -243,6 +245,7 @@ class MobileViewportManager final : public nsIDOMEventListener,
    * The software keyboard height.
    */
   mozilla::ScreenIntCoord mKeyboardHeight;
+  mozilla::Maybe<mozilla::ScreenIntCoord> mPendingKeyboardHeight;
 };
 
 #endif

layout/base/PresShell.cpp

@@ -11418,7 +11418,11 @@ void PresShell::MaybeRecreateMobileViewportManager(bool aAfterInitialization) {
           ("Created MVM %p (type %d) for URI %s", mMobileViewportManager.get(),
            (int)*mvmType, uri ? uri->GetSpecOrDefault().get() : "(null)"));
     }
+    if (BrowserChild* browserChild = BrowserChild::GetFrom(this)) {
+      mMobileViewportManager->UpdateKeyboardHeight(browserChild->GetKeyboardHeight());
+    }
   }
+
   if (aAfterInitialization) {
     // Setting the initial viewport will trigger a reflow.
     if (mMobileViewportManager) {

layout/base/nsPresContext.cpp

@@ -247,7 +247,6 @@ nsPresContext::nsPresContext(dom::Document* aDocument, nsPresContextType aType)
       mCurAppUnitsPerDevPixel(0),
       mDynamicToolbarMaxHeight(0),
       mDynamicToolbarHeight(0),
-      mKeyboardHeight(0),
       mPageSize(-1, -1),
       mPageScale(0.0),
       mPPScale(1.0f),
@@ -722,8 +721,6 @@ nsresult nsPresContext::Init(nsDeviceContext* aDeviceContext) {
 #if defined(MOZ_WIDGET_ANDROID)
   if (IsRootContentDocumentCrossProcess()) {
     if (BrowserChild* browserChild = BrowserChild::GetFrom(GetDocShell())) {
-      mKeyboardHeight = browserChild->GetKeyboardHeight();
-
       if (MOZ_LIKELY(!Preferences::HasUserValue(
               "layout.dynamic-toolbar-max-height"))) {
         mDynamicToolbarMaxHeight = browserChild->GetDynamicToolbarMaxHeight();
@@ -3129,7 +3126,7 @@ void nsPresContext::UpdateDynamicToolbarOffset(ScreenIntCoord aOffset) {
 
   dom::InteractiveWidget interactiveWidget = mDocument->InteractiveWidget();
   if (interactiveWidget == InteractiveWidget::OverlaysContent &&
-      mKeyboardHeight > 0) {
+      GetKeyboardHeight() > 0) {
     // On overlays-content mode, the toolbar offset change should NOT affect
     // the visual viewport while the software keyboard is being shown since
     // the toolbar will be positioned somewhere in the middle of the visual
@@ -3163,8 +3160,6 @@ void nsPresContext::UpdateDynamicToolbarOffset(ScreenIntCoord aOffset) {
 
 void nsPresContext::UpdateKeyboardHeight(ScreenIntCoord aHeight) {
   MOZ_ASSERT(IsRootContentDocumentCrossProcess());
-  mKeyboardHeight = aHeight;
-
   if (!mPresShell) {
     return;
   }
@@ -3175,8 +3170,13 @@ void nsPresContext::UpdateKeyboardHeight(ScreenIntCoord aHeight) {
   }
 }
 
+ScreenIntCoord nsPresContext::GetKeyboardHeight() const {
+  MobileViewportManager* mvm = mPresShell->GetMobileViewportManager();
+  return mvm ? mvm->GetKeyboardHeight() : ScreenIntCoord(0);
+}
+
 bool nsPresContext::IsKeyboardHiddenOrResizesContentMode() const {
-  return mKeyboardHeight == 0 ||
+  return GetKeyboardHeight() == 0 ||
          mDocument->InteractiveWidget() == InteractiveWidget::ResizesContent;
 }
 

layout/base/nsPresContext.h

@@ -442,7 +442,7 @@ class nsPresContext : public nsISupports, public mozilla::SupportsWeakPtr {
 
   void UpdateKeyboardHeight(mozilla::ScreenIntCoord aHeight);
 
-  mozilla::ScreenIntCoord GetKeyboardHeight() const { return mKeyboardHeight; }
+  mozilla::ScreenIntCoord GetKeyboardHeight() const;
 
   /**
    * Returns true if the software keyboard is hidden or
@@ -1247,8 +1247,6 @@ class nsPresContext : public nsISupports, public mozilla::SupportsWeakPtr {
   // The maximum height of the dynamic toolbar on mobile.
   mozilla::ScreenIntCoord mDynamicToolbarMaxHeight;
   mozilla::ScreenIntCoord mDynamicToolbarHeight;
-  // The software keyboard height.
-  mozilla::ScreenIntCoord mKeyboardHeight;
   // Safe area insets support
   mozilla::LayoutDeviceIntMargin mSafeAreaInsets;
   nsSize mPageSize;